Heat a large heavy nonstick skillet over medium-low heat. Meanwhile, brush one side of each bread slice with some of the melted butter. Place half the bread slices, buttered side down, on a plate. Sprinkle with chocolate and raspberries to within 1/4 inch of crusts. Top with remaining bread, buttered sides up. Place sandwiches, two at a time, in pan. Weight with a heavy skillet.
Grill sandwiches over medium-low heat for 6 to 8 minutes, until chocolate is melted and bread is golden brown, turning once midway through grilling time. Grill remaining sandwiches.
Slice in half to serve. Pass warm Chocolate Gravy for dipping.